Joseph Savage pleaded not guilty Monday at his arraignment before a federal magistrate in Pittsburgh, where federal prosecutors said the 34-year-old mailed the letter from the Fayette County Prison to 1400 Pennsylvania Avenue in Wash, DC.
The White House - as every president knows - is at 1600 Pennsylvania Avenue.
Authorities say Savage mailed the threat while he was awaiting trial in October 2012, and that it made it to the White House anyway, despite the erroneous address.
The U.S. attorney's office in Pittsburgh did not disclose the contents of the letter, beyond a description in a two-count indictment returned by a federal grand jury last month. According to the indictment, Savage threatened "to kill and to kidnap and to inflict bodily harm" on an unspecified member of the president's family and to "torture and murder the president upon being released from prison."
Savage, of West Leisenring, is serving up to 25 years at a state prison in Houtzdale, about 40 miles south of Pittsburgh. If he serves the maximum, he will be behind bars until 2037.
Savage's sentence stems from four separate cases. He was convicted of molesting a 9-year-old Uniontown girl, exposing himself to a 10-year-old girl in neighboring North Union Township, damaging a prisoner waiting room at a district judge's office and sending a threatening letter to the state police trooper who charged him.